1. Field of the Invention
The present invention relates to a peripheral interface device, and more particularly, to a peripheral interface device capable of supporting a plurality of interfaces, and a priority control method thereof.
2. Description of the Related Art
With development of information communications equipment, a variety of interface methods have been introduced, for example, Institute of Electrical and Electronics Engineers 1394 (IEEE1394), a universal serial bus (USB), a universal asynchronous receiver/transmitter (UART), a recommended standard 232 revision C (RS232C), etc. Among them, the IEEE1394 and the USB are widely employed in a computer as the interface methods.
Meanwhile, there is no limit to the number of peripherals that can be connected to the computer while the number of ports provided in the computer is limited. Accordingly, it is possible that a peripheral device can support the interface methods.
For example, a hard disc drive that is a representative computer peripheral device offers a capacity of tens of gigabytes today, and utilization of the hard disc drive continues to expand. Also, to increase mobility, portable hard disc drives have been introduced.
At present, an Intel-compatible computer supports 2 (two) hard disc drive buses, each of which can connect 2 hard discs disc drives (master and slave). Considering that 1 or 2 CD-ROM drives (or DVD-ROM drives) and 1 CD-RW drive are normally used, only 2 hard disc drives can be connected through the hard disc drive buses, and it is difficult to connect more than two hard disc drives.
Accordingly, the hard disc drives supporting multiple interface methods (interfaces), such as the IEEE1394 and the USB, are being introduced.
These hard disc drives supporting the multiple interfaces have a plurality of bridges (a bridge converts a signal of an interface method into a signal of another interface method) and selectively use one of the bridges. For example, a USB/integrated drive electronics (USB/IDE) bridge converts a signal of a USB interface method into a signal of an IDE interface that is a standard for a hard disc drive.
The hard disc drives supporting these multiple interfaces may be divided by a direct connection method and a multiplexer-using method.
A hard disc drive of the direct connection method has connection ports corresponding to respective interface methods and bridges connected to the respective connection ports. Which bridge is to be used is determined only by selection of a user.
A hard disc drive of the multiplexer-using method has connection ports corresponding to respective interface methods and bridges connected to the respective connection ports. Using a multiplexer, one of signals converted in bridges appropriate to respective interface methods is selectively used.
However, the hard disc drive of the direct connection method can neither identify the interface method nor correctly respond to an interface when 2 or more interfaces using different interface methods are connected to the computer, such that the interfaces cause defects or troubles in operation.
Also, in the hard disc drive of the multiplexer-using method, power is provided not only to a bridge being used but also to other bridges, which are not in use, such that other bridges also operate to cause noise and a waste of the power, and use of the multiplexer puts an obstacle to minimization of an external or portable hard disc drive.
As shown in FIG. 1, a hard disc drive of a conventional direct connection method includes an IEEE1394 port 102 to which an IEEE1394 connector can be connected, an IEEE1394 physical layer processor (PHY) 104 which processes a physical layer of an IEEE1394 signal, an IEEE1394/IDE bridge 106 which processes a link layer of the IEEE1394 signal, a USB port 108 to which a USB connector can be connected, a USB/IDE bridge 110 which processes a physical layer and a link layer of a USB signal, and an advanced technology attachment packet interface (ATAPI) bus connector 112.
In the hard disc drive shown in FIG. 1, a user selectively uses only one of the IEEE1394 port 102 and the USB port 108.
However, since in the hard disc drive of FIG. 1, the IEEE1394 physical layer processor 104, the IEEE1394/IDE bridge 106, and the USB/IDE bridge 110 always operate, if one method is used, a bridge of the other method wastes power and may cause noise into an ATAPI signal.
Also, if both the IEEE1394 port 102 and the USB port 108 are connected to the IEEE 1394 port 102 and the USB port 108, respectively, by mistake, the hard disc drive may not work properly.
FIG. 2 is a diagram showing another structure of another conventional portable hard disc drive that uses a multiplexer-using method.
As shown in FIG. 2, the hard disc drive of the conventional multiplexer-using method includes an IEEE1394 port 202 to which an IEEE1394 connector can be connected, an IEEE1394 physical layer processor 204 which processes a physical layer of an IEEE1394 signal, an IEEE1394/IDE bridge 206 which processes a link layer of the IEEE1394 signal; a USB port 208 to which a USB connector can be connected, a USB/IDE bridge 210 which processes a physical layer and a link layer of a USB signal, a multiplexer/demultiplexer 214 which selectively outputs one of outputs of the IEEE1394/IDE bridge 206 and the USB/IDE bridge 210, and an ATAPI bus connector 212.
In the hard disc drive of FIG. 2, an operation of the multiplexer/demultiplexer 214 is controlled by a signal provided to the USB port 208. A USB connector includes a power pin (Vp), a ground pin (GROUND), and 2 differential signal pins (D, D2). A selection operation of the multiplexer/demultiplexer 214 is controlled by USB power (Vusb) provided to the power pin (Vp). That is, if the USB power (Vusb) is provided, the multiplexer/demultiplexer 214 operates to connect the USB/IDE bridge 210 to the ATAPI bus connector 212 while if the USB power (Vusb) is not provided, the IEEE1394/IDE bridge 206 is connected to the ATAPI bus connector 212.
By the operation of the multiplexer/demultiplexer 214, when both the IEEE1394 port 102 and the USB port 108 are connected, the hard disc drive of FIG. 2 appropriately determines the interface method being used and responds to it.
However, also in the hard disc drive of FIG. 2 like as in the hard disc drive of FIG. 1, the IEEE1394 physical layer processor 204, the IEEE1394/IDE bridge 206, and the USB/IDE bridge 210 always operate even if one method is used, and the bridge of the other method wastes the power and may cause the noise into the ATAPI signal.
Meanwhile, since the multiplexer/demultiplexer 214 should correspond to the number of IDE-type signal lines, it is difficult to minimize a size of the portable hard disc drive, and a switching operation may cause noise.